Papers by Murali Malliga Raman
Aims: Mesenchymal stem/stromal cells (MSCs) hold promises for the treatment of diverse diseases a... more Aims: Mesenchymal stem/stromal cells (MSCs) hold promises for the treatment of diverse diseases and regener-ation of injured tissues. Genetic modification of MSCs through gene delivery might enhance their therapeutic potential. Adiponectin has been appeared as a potential biomarker for predicting various diseases. Plasma adiponectin levels are negatively correlated with various metabolic and vascular diseases and supplementation of exogenous adiponectin ameliorates the diseases. This study aims to develop adiponectin secreting genetically modified MSCs (GM-MSCs) as a potent strategic tool to complement endogenous adiponectin for the treatment of adiponectin deficiency diseases. Main methods: Human bone marrow derived MSCs were isolated, expanded in vitro and transfected with adiponectin gene containing plasmid vector. Total RNA was extracted and cDNA was prepared by reverse transcription polymerase chain reaction (RT-PCR). The expression of adiponectin gene and protein in GM-MSCs was analyzed by PCR and Western blotting respectively. The secretion of adiponectin protein from GM-MSCs was analyzed by enzyme-linked immunosorbent assay. Key findings: The expression of adiponectin gene and plasmid DNA was detected in GM-MSCs but not in control group of MSCs. Adiponectin gene expression was detected in GM-MSCs at 2, 7, 14, 21 and 28 days after transfec-tion. Western blotting analysis revealed the expression of adiponectin protein only in GM-MSCs. The GM-MSCs stably secreted adiponectin protein into culture media at least for 4 weeks. Significance: GM-MSCs express and secret adiponectin protein. Therefore, these adiponectin secreting GM-MSCs could be instrumental for the supplementation of adiponectin in the treatment of adiponectin deficiency related diseases.
Quercetin is a bioactive compound with anti-inflammatory, antioxidant and anticancer properties. ... more Quercetin is a bioactive compound with anti-inflammatory, antioxidant and anticancer properties. This study exemplifies the differential cytotoxic activity of Quercetin on two human colonic cancer cell lines, HT29 and HCT15. IC 50 of Quercetin for HT29 and HCT15 cells were 42.5 mM and 77.4 mM, respectively. Activation of caspase-3, increased level of cytosolic cytochrome c, decreased levels of pAkt, pGSK-3b and cyclin D1 in 40 mM Quercetin treated HT29 cells alone. Though, nuclear translocation of NFkB was increased in 40 mM Quercetin treated HT29 and HCT15 cells, over expression of COX-2 was observed in 40 mM Quercetin treated HT29 cells, whereas, Quercetin treated HCT15 cells did not expressed COX-2. Increased generation of reactive oxygen species (ROS) was observed only in Quercetin treated HT29 cells, which is due to over expression of COX-2, as COX-2 silencing inhibited Quercetin induced apoptosis and ROS generation. Insilico analysis provided evidence that Quercetin could partially inhibit COX-2 enzyme by binding to subunit A which has peroxidase activity and serves as source of ROS. However, Quercetin showed minimal effect on normal intestinal epithelial cells i,e IEC-6. To conclude, differential sensitivity of two cancer cells, HT29 and HCT15, to Quercetin depends on COX-2 dependent ROS generation that induces apoptosis and inhibits cell survival.
Tissue engineering aims to generate or facilitate regrowth or healing of damaged tissues by apply... more Tissue engineering aims to generate or facilitate regrowth or healing of damaged tissues by applying a combination of biomaterials, cells, and bioactive signaling molecules. In this regard, growth factors clearly play important roles in regulating cellular fate. However, uncontrolled release of growth factors has been demonstrated to produce severe side effects on the surrounding tissues. In this study, poly(lactic-co-glycolic acid) (PLGA) micro-spheres (MS) incorporated three-dimensional (3D) CORAGRAF scaffolds were engineered to achieve controlled release of platelet-derived growth factor-BB (PDGF-BB) for the differentiation of stem cells within the 3D polymer network. Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and microtomography were applied to characterize the fabricated scaffolds. In vitro study revealed that the CORAGRAF-PLGA-PDGF-BB scaffold system enhanced the release of PDGF-BB for the regulation of cell behavior. Stromal cell attachment, viability, release of osteogenic differentiation markers such as osteocalcin, and upregulation of osteogenic gene expression exhibited positive response. Overall, the developed scaffold system was noted to support rapid cell expansion and differentiation of stromal cells into osteogenic cells in vitro for bone tissue engineering applications.
It has been demonstrated that carbon (C) doped aluminium oxide (Al 2 O 3) nanocomposite (C À 0.01... more It has been demonstrated that carbon (C) doped aluminium oxide (Al 2 O 3) nanocomposite (C À 0.012 wt%) had greater wear resistance and lower surface grains pull out percentage when compared with monolithic Al 2 O 3. In the present study, we investigated the physicochemical, micro-and nano-mechanical, cell attachment, in vitro biocompatibility and osteogenic differentiation properties of Al 2 O 3 doped carbon (0.012 wt%) nanocomposite (Al 2 O 3 /C). Data were compared to values obtained for monolithic alumina (Al 2 O 3). The calcined Al 2 O 3 /C nanocomposite was densified using cold isostatic pressing and followed by pressureless sintering. For physicochemical and microstructural characterisa-tion, Energy dispersive X-ray (EDX), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photo-emission spectrometer (XPS) were used. EDX, XRD peaks and Raman spectroscopy demonstrated correlating to Al 2 O 3 /C. Surface profiling and contact angle investigations demonstrated highly contoured micro-surface topography. The micro and nano-hardness indicate an improved wear resistance of the Al 2 O 3 /C when compared with monolithic Al 2 O 3. SEM, confocal images and alamar blue reduction assay suggested good cell attachment and proliferation of human bone marrow derived mesenchymal stromal cells (hBMSCs). Osteogenic protein and gene expression indicated Al 2 O 3 /C had a significant osteogenic potential (p o0.05) when compared with Al 2 O 3. In conclusion, our novel Al 2 O 3 /C nanocomposite had improved mechanical properties. It also supports cell attachment and proliferation which are comparable to Al 2 O 3. However, Al 2 O 3 /C has a significant osteogenic potential than that of Al 2 O 3. These findings suggest that Al 2 O 3 /C nanocomposite is superior to Al 2 O 3 and thus has a greater potential for use in orthopaedic applications.
Previous studies have shown that platelet concentrates used in conjunction with appropriate growt... more Previous studies have shown that platelet concentrates used in conjunction with appropriate growth media enhance osteogenic differentiation of human mesenchymal stromal cells (hMSCs). However, their potential in inducing osteogenesis of hMSCs when cultured in serum free medium has not been explored. Furthermore, the resulting osteogenic molecular signatures of the hMSCs have not been compared to standard osteogenic medium. We studied the effect of infrequent supplementation (8-day interval) of 15% non-activated platelet-rich concentrate (PRC) in serum free medium on hMSCs proliferation and differentiation throughout a course of 24 days, and compared the effect with those cultured in a standard osteogenic medium (OM). Cell proliferation was analyzed by alamar blue assay. Gene expression of osteogenic markers (Runx2, Collagen1, Alkaline Phosphatase, Bone morphogenetic protein 2, Osteopontin, Osteocalcin, Osteonectin) were analyzed using Q-PCR. Immunocytochemical staining for osteocalcin, osteopontin and transcription factor Runx2 were done at 8, 16 and 24 days. Biochemical assays for the expression of ALP and osteocalcin were also performed at these time-points. Osteogenic differentiation was further confirmed qualitatively by Alizarin Red S staining that was quantified using cetylpyridinium chloride. Results showed that PRC supplemented in serum free medium enhanced hMSC proliferation, which peaked at day 16. The temporal pattern of gene expression of hMSCs under the influence of PRC was comparable to that of the osteogenic media, but at a greater extent at specific time points. Immunocytochemical staining revealed stronger staining for Runx2 in the PRC-treated group compared to OM, while the staining for Osteocalcin and Osteopontin were comparable in both groups. ALP activity and Osteocalcin/DNA level were higher in the PRC group. Cells in the PRC group had similar level of bone mineralization as those cultured in OM, as reflected by the intensity of Alizarin red stain. Collectively, these results demonstrate a great potential of PRC alone in inducing proliferation of hMSCs without any influence from other lineage-specific growth media. PRC alone has similar capacity to enhance hMSC osteogenic differentiation as a standard OM, without changing the temporal profile of the differentiation process.
This study investigated the effect of composite scaffolds composed of poly (octanediol citrate) (... more This study investigated the effect of composite scaffolds composed of poly (octanediol citrate) (POC) and a bioactive glass (composition, 48%SiO 2 -12%CaO-32%ZnO-8%Ga 2 O 3 ) on the growth and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). All the scaffolds, regardless of the amount of bioglass incorporation, were able to support the growth of hBMSCs and guide their osteogenic differentiation without osteogenic media stimulation. The expression of bone-associated genes (runt-related transcription factor 2, type I collagen, bone morphogenetic protein 2, osteonectin and osteocalcin) was significantly increased by a culture time of up to 2 weeks, particularly for the composite scaffold loaded with 10% bioactive glass. The composite scaffolds significantly stimulated alkaline phosphatase (ALP) activity compared to the pure POC scaffold. Cellular mineralization of the secreted extracellular matrix illustrated a higher calcium level on the composites than on the pure POC and increased with culture time. These results suggest that composite scaffolds of POC and a bioactive glass can provide favourable conditions for osteogenic differentiation of hBMSCs and can potentially be used to induce bone healing and regeneration.
Background: Fracture healing in bone gap is one of the major challenges encountered in Orthopedic... more Background: Fracture healing in bone gap is one of the major challenges encountered in Orthopedic Surgery. At present, the treatment includes bone graft, employing either internal or external fixation which has a significant impact on the patient, family and even society. New drugs are emerging in the markets such as anabolic bone-forming agents including teriparatide and strontium ranelate to stimulate bone growth. Based on the mechanism of their actions, we embarked on a study on the healing of a fractured ulna with bone gap in a rabbit model. We segregated ten rabbits into two groups: five rabbits in the test group and five rabbits in the control group. We created a 5 mm bone gap in the ulna bone, removing the periosteum as well. Rabbits in the test group received 450 mg/kg of strontium ranelate via oral administration, daily, for six weeks. The x-rays, CT scans and blood tests were performed every two weeks. At the end of six weeks, the rabbits were sacrificed, and the radius and ulna bones harvested for histopathological examination. Results: Based on the x-rays and CT scans, fracture healing or bone formation was observed to be faster in the control group. From the x-ray findings, 80 % of the fracture united and by CT scan, 60 % of the fracture united in the control group at the end of the six-week study. None of the fractures united in the test group. However, the histopathology report showed that a callus of different stages was being formed in both groups, consisting of 80 % of bone. The serum levels of osteocalcin and alkaline phosphatase initially remained similar up to three weeks and changed slightly at the end of six weeks.
Diopside was synthesized from biowaste (Eggshell) by sol–gel combustion method at low calcination... more Diopside was synthesized from biowaste (Eggshell) by sol–gel combustion method at low calcination temperature and the influence of two different fuels (urea, L-alanine) on the phase formation temperature, physical and biological properties of the resultant diopside was studied. The synthesized materials were characterized by heating microscopy, FTIR, XRD, BET, SEM and EDAX techniques. BET analysis reveals particles were of submicron size with porosity in the nanometer range. Bone-like apatite deposition ability of diopside scaffolds was examined under static and circulation mode of SBF (Simulated Body Fluid). It was noticed that diopside has the capability to deposit HAP (hydroxyapatite) within the early stages of immersion. ICP-OES analysis indicates release of Ca, Mg, Si ions and removal of P ions from the SBF, but in different quantities from diopside scaffolds. Cytocompatability studies on human bone marrow stromal cells (hBMSCs) revealed good cellular attachment on the surface of diopside scaffolds and formation of extracellular matrix (ECM). This study suggests that the usage of eggshell biowaste as calcium source provides an effective substitute for synthetic starting materials to fabricate bioproducts for biomedical applications.
Presence of sulfated polysaccharides like heparan sulphate has often been implicated in the regul... more Presence of sulfated polysaccharides like heparan sulphate has often been implicated in the regulation of chondrogenesis. However, recently there has been a plethora of interest in the use of non-animal extracted analogs of heparan sulphate. Here we remodeled alginate (1.5%) by incorporating fucoidan (0.5%), a natural sulphated polysaccharide extracted from seaweeds to form a composite hydrogel (Al-Fu), capable of enhancing chondrogenesis of human mesenchymal stromal cells (hMSCs). We confirmed the efficiency of fucoidan incorporation by FTIR and EDX analysis. Further, its ability to support hMSC attachment and chondrogenic differentiation was confirmed by SEM, biochemical glycosaminoglycan quantification, real-time quantitative PCR and immunocytochemical analyses of chondrogenic markers Sox-9, Collagen II, Aggrecan and COMP. Effect of Al-Fu hydrogel on hMSC hypertrophy was also confirmed by the downregulation of hypertrophic genes Collagen X and Runx2. This composite scaffold can hence be used as a cartilage biomimetic biomaterial to drive hMSC chondrogenesis and for other cartilage repair based therapies.
In our previous study, we reported the fabrication and characterization of a novel tricalcium pho... more In our previous study, we reported the fabrication and characterization of a novel tricalcium phosphate-fucoidan-chitosan (TCP-Fu-Ch) biocomposite scaffold. However, the previous report did not show whether the biocomposite scaffold can exhibit osteogenic differentiation of human bone marrow stromal cells in osteogenic media and normal media supplemented with platelet-derived growth factor (PDGF-BB). On day 15, the release of osteocalcin, was significant in the TCP-Fu-Ch scaffold, when compared with that in the TCP-Ch scaffold, and the level of release was approximately 8 and 6 ng/ml in osteogenic and normal media supplemented with PDGF-BB, respectively. Scanning electron microscopy of the TCP-Fu-Ch scaffold demonstrated mineralization and apatite layer formation on day 14, while the addition of PDGF-BB also improved the osteogenic differentiation of the scaffold. An array of gene expression analysis demonstrated that TCP-Fu-Ch scaffold cultured in osteogenic and normal media supplemented with PDGF-BB showed significant improvement in the expression of collagen 1, Runt-related transcription factor 2, osteonectin, bone gamma-carboxyglutamate protein, alkaline phosphatase, and PPA2, but a decline in the expression of integrin. Altogether, the present study demonstrated that fucoidan-incorporated TCP-Ch scaffold could be used in the differentiation of bone marrow stromal cells and can be a potential candidate for the treatment of bone-related ailments through tissue engineering technology. The use of metallic plates in order to support the defective region of the bone during the early stages of bone healing have a tendency to creep and deform permanently under mechanical stresses, and thus, require reinforcements. Hence, the field of tissue engineering is moving towards the development of composite scaffolds that have mechanically supportive structures that can resist creep failure whilst exhibiting osteoconductive as well as oste-oinductive capabilities 1. The present therapeutic approaches in repairing critical-size bone defects, such as those caused by tumor resection or trauma, include the use of autographs, allografts, metals, porous ceramics, and so on; however, each of these methods has their own pros and cons 2. Since tissue engineering emerged as an alternative to overcome these limitations, particularly the structural and functional tissue in combination with scaffold and growth factors. The major aim of tissue engineering was to mimic the bone structure and good physiological function. Among various cell sources used, progenitor cells are the key for better tissue healing in combination with growth factor and scaffolding material 3. Previous studies have shown that periosteal provides a good source of cells which can readily differentiate and lay down bone. However, the choice in most cases is bone marrow due to the limited availability of periosteal tissue 4. The potential of a particular material to be used as a scaffold on which stem cells can attach, proliferate and mineralize are termed as osteoconductive 5. Though different materials have been used for bone tissue
Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture an... more Chondrogenic differentiation of mesenchymal stromal cells (MSCs) in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model for in vitro chondrogenesis. However, comparative characterization between differentiation , hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM) was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG) analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05) chondrogenic but lower hypertrophic (p < 0.05) gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis. How to cite this article Dashtdar et al. (2016), Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads. PeerJ 4:e1650
Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic... more Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic differentiation in favorable microenvironment and with growth factor supplementation. In this study, the osteogenic potential of electrospun poly-l-lactide/hydroxyapatite/collagen (PLLA/Col/HA, PLLA/HA and PLLA/Col) scaffolds were tested in vitro with the supplementation of platelet derived growth factor-BB (PDGF-BB). Cell attachment and topography, mineralization, extracellular matrix protein localization, and gene expression of the human mesenchymal stromal cells were compared between the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA. The levels of osteocalcin, calcium, and mineralization were significantly greater in the PLLA/Col/HA and PLLA/HA compared with PLLA/Col. High expression of fibronectin, intracellular adhesion molecule, cadherin, and collagen 1 (Col1) suggests that PLLA/Col/HA and PLLA/HA scaffolds had superior osteoinductivity than PLLA/Col. Additionally, osteopontin, osteocalcin, osterix, Runt-related transcription factor 2 (Runx2), and bone morphogenic protein (BMP2) expression were higher in PLLA/Col/HA and PLLA/HA compared with PLLA/Col. In comparison with PLLA/Col, the PLLA/Col/HA and PLLA/HA scaffolds presented a significant upregulation of the genes Runx2, Col 1, Integrin, osteonectin (ON), bone gamma-carboxyglutamic acid-containing protein (BGALP), osteopontin (OPN), and BMP2. The upregulation of these genes was further increased with PDGF-BB supplementation. These results show that PDGF-BB acts synergistically with PLLA/Col/HA and PLLA/HA to enhance the osteogenic differentiation potential. Therefore, this combination can be used for the rapid expansion of bone marrow stromal cells into bone-forming cells for tissue engineering.
Background: In the present study, thirty six male Sprague Dawley rats were randomly divided into ... more Background: In the present study, thirty six male Sprague Dawley rats were randomly divided into six groups and were injected with varying doses of alloxan (Ax) and nicotinamide (NA). The serum levels of glucose, insulin, and adiponectin were measured weekly up to 4 weeks. Results: Elevated levels of glucose were observed in all groups on days 7, 14, 21, and 28, except in groups a and f (control). The serum insulin levels were significantly elevated in groups b and c on day 7, when compared with that in group f, whereas a decrease in the serum insulin levels was observed in groups d and e on days 21 and 28. The adiponectin levels showed inconsistencies on days 7 and 14. However, significant decrease in the adiponectin levels was observed on days 21 and 28. Histological section of the pancreas showed mild (group a), moderate (group b) to severe (groups c, d, and e) degenerative changes. Concomitant fatty changes in the liver and inflammatory infiltration of the kidney were markedly observed in all the treated groups, when compared to control. Conclusion: These results suggested that the use of selective combination of Ax120 þ NA50 injection demonstrated type II diabetes mellitus in rats.
We developed tricalcium phosphate-chitosan-fucoidan biocomposite scaffold (TCP-Ch-Fu) by using th... more We developed tricalcium phosphate-chitosan-fucoidan biocomposite scaffold (TCP-Ch-Fu) by using the freeze-drying technique. The fabricated biocomposite scaffolds were analyzed by spectroscopy and porosity measurement. The biomechanical properties of scaffolds were assessed by compression test and the results suggested that the incorporation of Fucoidan into the biocomposite improves the compression strength of scaffolds. Biomineralization of scaffolds was evaluated by soaking them in simulated body fluid and the results revealed that the addition of Fucoidan into the scaffolds enhanced the formation of apatite layer on the surface of biocomposite after 7 days of immersion. Alamar Blue assay confirmed that the cell viability of human-derived bone marrow stromal cell was superior in the TCP-Ch-Fuscaffold. The addition of Fucoidan to TCP-Ch increased the release of osteocalcin, confirming that it can support osteogenic differentiation of human mesenchymal stromal cells in in vitro culture. Thus, TCP-Ch-Fu could be a potential candidate for bone-tissue engineering applications.
Aim: To compare the effect of bovine bone derived porous hydroxyapatite (BDHA) scaffold on prolif... more Aim: To compare the effect of bovine bone derived porous hydroxyapatite (BDHA) scaffold on proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hMSCs) compared with commercial hydroxyapatite (CHA) scaffold. Materials and methods: The porosity and pore size were analyzed using micro-CT. The biocompatibility was demonstrated by alamar blue assay, and cell attachment through SEM and Hoechst staining. The osteogenic differentiation was demonstrated using biochemical assay and osteogenic gene expression. Results: BDHA and CHA scaffolds showed porosity of 76.6 ± 0.6 and 64.3 ± 0.3% and pore size diameter of 0.04–0.25 and 0.1–2.6 mm, respectively. hMSCs proliferation, ALP activity, osteocalcin secretion and osteogenic gene expression are comparable in both the scaffolds. Conclusion: These results demonstrated that BDHA is biocompatible, supports cell adhesion and promotes proliferation and osteogenic differentiation.
In the present study, we developed an unmodified/raw Medium chain length –PHA (MCL-PHA) polyhydrox... more In the present study, we developed an unmodified/raw Medium chain length –PHA (MCL-PHA) polyhydroxyalkanoate (PHA), natural microbial polyester by using cost-effective saponified palm kernel oil (SPKO) technique. The functional groups, elemental composition, phase purity, water contact angle, and in vitro human-derived mesenchymal stromal cell attachment were examined. FTIR confirmed the presence of functional groups corresponding to alkyl halide, alkyne, hydroxyl group, and alkane groups, while XRD and EDX results revealed its phase purity and presence of elements such as carbon and oxygen respectively. SEM and confocal microscope analyses revealed that the bio-material supports cell attachment and this was further confirmed through cell viability assay. In conclusion, the characterization and compatibility studies revealed that this novel scaffold could be a potential candidate for possible tissue engineering applications.
Platelet rich concentrate (PRC) is a natural adjuvant that aids in human mesenchymal stromal cell... more Platelet rich concentrate (PRC) is a natural adjuvant that aids in human mesenchymal stromal cell (hMSC) proliferation in vitro; however, its role requires further exploration.This studywas conducted to determine the optimal concentration of PRC required for achieving themaximal proliferation, and the need for activating the platelets to achieve this effect, and if PRC could independently induce early differentiation of hMSC.Thegene expression ofmarkers for osteocytes (ALP,RUNX2), chondrocytes (SOX9,COL2A1), and adipocytes (PPAR-g) was determined at each time point in hMSC treated with 15% activated and nonactivated PRC since maximal proliferative effect was achieved at this concentration. The isolated PRC had approximately fourfold higher platelet count than whole blood. There was no significant difference in hMSC proliferation between the activated and nonactivated PRC. Only RUNX2 and SOX9 genes were upregulated throughout the 8 days. However, protein expression study showed formation of oil globules from day 4, significant increase in ALP at days 6 and 8 (𝑃 ≤ 0.05), and increased glycosaminoglycan levels at all time points (p < 0.05), suggesting the early differentiation of hMSC into osteogenic and adipogenic lineages.This study demonstrates that the use of PRC increased hMSC proliferation and induced early differentiation of hMSC into multiple mesenchymal lineages, without preactivation or addition of differentiation medium.
A comparative study on the in vitro osteogenic potential of electrospun poly-L-lactide/hydroxyapa... more A comparative study on the in vitro osteogenic potential of electrospun poly-L-lactide/hydroxyapatite/collagen (PLLA/HA/
Col, PLLA/HA, and PLLA/Col) scaffolds was conducted. The morphology, chemical composition, and surface roughness of
the fibrous scaffolds were examined. Furthermore, cell attachment, distribution, morphology, mineralization, extracellular
matrix protein localization, and gene expression of human mesenchymal stromal cells (hMSCs) differentiated on the fibrous
scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA were also analyzed. The electrospun scaffolds with a diameter of 200–
950 nm demonstrated well-formed interconnected fibrous network structure, which supported the growth of hMSCs. When
compared with PLLA/HA and PLLA/Col scaffolds, PLLA/Col/HA scaffolds presented a higher density of viable cells and
significant upregulation of genes associated with osteogenic lineage, which were achieved without the use of specific
medium or growth factors. These results were supported by the elevated levels of calcium, osteocalcin, and mineralization
(P<0.05) observed at different time points (0, 7, 14, and 21 days). Furthermore, electron microscopic observations and
fibronectin localization revealed that PLLA/Col/HA scaffolds exhibited superior osteoinductivity, when compared with PLLA/
Col or PLLA/HA scaffolds. These findings indicated that the fibrous structure and synergistic action of Col and nano-HA with
high-molecular-weight PLLA played a vital role in inducing osteogenic differentiation of hMSCs. The data obtained in this
study demonstrated that the developed fibrous PLLA/Col/HA biocomposite scaffold may be supportive for stem cell based
therapies for bone repair, when compared with the other two scaffolds.
Pilon fractures are commonly caused by high energy trauma and can result in long-term immobilizat... more Pilon fractures are commonly caused by high energy trauma and can result in long-term immobilization of patients. The use of an external fixator i.e. the (1) Delta, (2) Mitkovic or (3) Unilateral frame for treating type III pilon fractures is generally recommended by many experts owing to the stability provided by these constructs. This allows this type of fracture to heal quickly whilst permitting early mobilization. However, the stability of one fixator over the other has not been previously demonstrated. This study was conducted to determine the biomechanical stability of these external fixators in type III pilon fractures using finite element modelling. Three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones were reconstructed from previously obtained CT datasets. Bones were assigned with isotropic material properties, while the cartilage was assigned as hyperelastic springs with Mooney-Rivlin properties. Axial loads of 350N and 70N were applied at the tibia to simulate the stance and the swing phase of a gait cycle. To prevent rigid body motion, the calcaneus and metatarsals were fixed distally in all degrees of freedom. The results indicate that the model with the Delta frame produced the lowest relative micromovement (0.03mm) compared to the Mitkovic (0.05mm) and Unilateral (0.42mm) fixators during the stance phase. The highest stress concentrations were found at the pin of the Unilateral external fixator (509.2MPa) compared to the Mitkovic (286.0MPa) and the Delta (266.7MPa) frames. In conclusion, the Delta external fixator was found to be the most stable external fixator for treating type III pilon fractures.
Subtalar dislocation is a rare injury caused by high-energy trauma. Current treatment strategies ... more Subtalar dislocation is a rare injury caused by high-energy trauma. Current treatment strategies include leg casts, internal fixation and external fixation. Among these, external fixators are the most commonly used as this method is believed to provide better stabilization. However, the biomechanical stability provided by these fixators has not been demonstrated. This biomechanical study compares two commonly used external fixators, i.e. Mitkovic and Delta. CT imaging data were used to reconstruct three-dimensional models of the tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms and five metatarsal bones. The 3D models of the bones and cartilages were then converted into four-noded linear tetrahedral elements, whilst the ligaments were modelled with linear spring elements. Bones and cartilage were idealized as homogeneous, isotropic and linear. To simulate loading during walking, axial loading (70N during the swing and 350N during the stance phase) was applied at the end of diaphyseal tibia. The results demonstrate that the Mitkovic fixator produced greater displacement (peak 3.0mm and 15.6mm) compared to the Delta fixator (peak 0.8mm and 3.9mm), in both the swing and stance phase, respectively. This study demonstrates that the Delta external fixator provides superior stability over the Mitkovic fixator. The Delta fixator may be more effective in treating subtalar dislocation.
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Papers by Murali Malliga Raman
Col, PLLA/HA, and PLLA/Col) scaffolds was conducted. The morphology, chemical composition, and surface roughness of
the fibrous scaffolds were examined. Furthermore, cell attachment, distribution, morphology, mineralization, extracellular
matrix protein localization, and gene expression of human mesenchymal stromal cells (hMSCs) differentiated on the fibrous
scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA were also analyzed. The electrospun scaffolds with a diameter of 200–
950 nm demonstrated well-formed interconnected fibrous network structure, which supported the growth of hMSCs. When
compared with PLLA/HA and PLLA/Col scaffolds, PLLA/Col/HA scaffolds presented a higher density of viable cells and
significant upregulation of genes associated with osteogenic lineage, which were achieved without the use of specific
medium or growth factors. These results were supported by the elevated levels of calcium, osteocalcin, and mineralization
(P<0.05) observed at different time points (0, 7, 14, and 21 days). Furthermore, electron microscopic observations and
fibronectin localization revealed that PLLA/Col/HA scaffolds exhibited superior osteoinductivity, when compared with PLLA/
Col or PLLA/HA scaffolds. These findings indicated that the fibrous structure and synergistic action of Col and nano-HA with
high-molecular-weight PLLA played a vital role in inducing osteogenic differentiation of hMSCs. The data obtained in this
study demonstrated that the developed fibrous PLLA/Col/HA biocomposite scaffold may be supportive for stem cell based
therapies for bone repair, when compared with the other two scaffolds.
Col, PLLA/HA, and PLLA/Col) scaffolds was conducted. The morphology, chemical composition, and surface roughness of
the fibrous scaffolds were examined. Furthermore, cell attachment, distribution, morphology, mineralization, extracellular
matrix protein localization, and gene expression of human mesenchymal stromal cells (hMSCs) differentiated on the fibrous
scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA were also analyzed. The electrospun scaffolds with a diameter of 200–
950 nm demonstrated well-formed interconnected fibrous network structure, which supported the growth of hMSCs. When
compared with PLLA/HA and PLLA/Col scaffolds, PLLA/Col/HA scaffolds presented a higher density of viable cells and
significant upregulation of genes associated with osteogenic lineage, which were achieved without the use of specific
medium or growth factors. These results were supported by the elevated levels of calcium, osteocalcin, and mineralization
(P<0.05) observed at different time points (0, 7, 14, and 21 days). Furthermore, electron microscopic observations and
fibronectin localization revealed that PLLA/Col/HA scaffolds exhibited superior osteoinductivity, when compared with PLLA/
Col or PLLA/HA scaffolds. These findings indicated that the fibrous structure and synergistic action of Col and nano-HA with
high-molecular-weight PLLA played a vital role in inducing osteogenic differentiation of hMSCs. The data obtained in this
study demonstrated that the developed fibrous PLLA/Col/HA biocomposite scaffold may be supportive for stem cell based
therapies for bone repair, when compared with the other two scaffolds.